May Have More Than One Choice Consider The Multiple Regression Model With Two Re

May have more than one choice:

Consider the multiple regression model with two regressors X1 and X2, where both variables are determinants of the dependent variable. When omitting X2from the​ regression,there will be omitted variable bias for :

A. if  X1 and X2  are correlated.

B. only if X2 is a dummy variable.

C. if  X2 has impact on Y (dependent variable)

D. always